Self-adjusting pinking shears



April 27, 1954 s SHALER 2,676,401

SELF-ADJUSTING PINKING SHEARS Filed March 16, 1950 2 Sheets-Sheet 1 INVENTOR 541/4 5710945 7 5 ATTORNEY Filed March 16, 1950 2 Sheets-Sheet 2 INVENTOR 3O 34 5004 5mm. ER

ATTO

,since, in any event, the

may be adjusted to place under desired stress a spring washer positioned between the levers and having an underlying flat washer 6. The levers are provided with, appropriate handles 1 and 8 such as are commonly found on shears and through the manipulation of which relative pivotal movement is imparted to the levers.

Positioned near the forward ends of the levers l and 2 are guide pins 9 and ID and said levers also carry guide pins II and |2 positioned between the fulcrum pivot 3 and the handles. The pivot pin 9 is shown as spaced from the fulcrum pivot 3 a distance equal to the spacing of the pin ID from such pivot. Likewise the pin l is shown as spaced from the pivot 3 the same distance as the pin l2. However, the spacing of the pins H and I2 from the fulcrum pin 3 is shown as somewhat greater than the spacing of the pins 9 and Hi from such fulcrum pin. However,

the particular spacing of these pins may be changed without departing fIOIIlIthlS invention, floating character of the follower blade l5 will permit the self-centering of the'teeth as they successively coact with one another.

Mounted on the pins 9 and 12 is, a so-called .captive blade l4, while mounted on the pins l0 and H is a follower blade I5. Figure 6 of the drawings schematically illustrates the relation of these parts. The blades are secured to the levers by the pins 9, l0,

H and [2 which may be of any explained, the captive lever I and is anchored against longitudinal appropriate construction, although, by preference, bolts with stepped heads or shouldered screws are employed for this purpose, so that the pins may be rigidly secured to the levers, while permitting pivotal or sliding movement or both, I

asthe case may levers.

In this construction,

be, between the blades and the the pin 9 passes through a closefittingcircular perforation 9a in the, secured to the forcaptive blade I4 which is thus ward end of thelever l and thereby made captive against longitudinal movement relative thereto. The pin l2, however, extends through an elongated slot It in the rear end of the blade |4,,so as to permit of pivotal movement levers and between the levers and blade I4. I I I I I The rear end of the follower blade l5 has; a slot coacting with the pin H in the same manner as the pin |2 coacts with the; slot |6, but the pin In at the forward end of the lever'2 passes through an elongated slot 18in this blade. The

the captive pins H) and H thus support the follower blade for longitudinal rectilinear movement relative to and in contradistinction to the captfve blade] twhich is secured against longitudinal movementbythe close fitting connecting pin l. I I I In practice I preferably stamp the blades l4 and I5 from sheet metalof such thickness to impart adequate strength and durability. In this stamping operation, longitudinal bosses l9 and 20 may be formed on the blades, as shown in Figures 1-3, to longitudinally stiffen them The portions of the blades, which constitutethe jaws of the shears and are adapted to coact with one between the one tooth of the other 'tively-act as a stop -of theslots H and I1 latter blade is free "z nd the blade m.

the pins m. and n pedient of mounting throughout the fectually cut, notwithstanding lack ,ity between consecutive teeth of either or both that, at least one of floating movement so self-centering of the ture of this invention could not be present.

ant a ioi only so far as shown in Figures 1 and 6, which leaves at least one tooth of one blade in mesh with at least one tooth of the other blade. With this arrangement the teeth of the two blades never leave meshing relation. At the start of the out, certain teeth of both blades are in mesh and, as the cut proceeds, the successive teeth of both blades, from the rear end of the flanges 2| and 22 to the forward ends of said flanges, consecutively mesh with one another as they pass through one another in'carrying" out the cutting operation. At the end of the cut, at least one tooth of each blade remains in mesh with at least II blade, so that, when the jaws are opened again, the teeth of the two blades successively mesh with one another in reverse order as they return to initial, fully opened position of the jaws. Thus the pins 9 and I2 collecto limit the opening movement shears, while a stop projection 24 on the handle 3 acts to limit the extent of .closing movement by engagement with an adjacent portion of the handle 1. I

During theopening and closing of the jaws as blade Hi moves with the of the jaws of the movement relative thereto. However, by virtue in the follower blade, this I I for longitudinal floating movement with respect to both thelevers l and Such being the case, the position of the follower blade with respect to I I I I is controlled at all times by the interfitting relation of the particular teeth of the two jaws which are at that time in mesh.

Inother words, when any particular tooth of one blade is brought into mesh with the corresponding space between teeth of the other blade, that tooth will automatically center itself in said space and autogenously shift the follower blade sufficiently to permit this self-centering action to take place. As a consequence of this fact, either or both the shaping or spacing of the consecutive teeth of the two blades may be somewhat inaccurate and yet the self-centering of these teeth, as they cooperate with one another,

will automatically compensate for such inaclcuracy and permit said teeth to efficiently cut the material between them.

It will thus be manifest that by the simple exthe two blades for relative longitudinal movement, the self-centering of the cutting teeth will automatically result and thus enable the corresponding individual teeth length of the two jaws to cfof uniformjaws or slight misplacement of the fulcrum pivot of the shears. Consequently, the manufacture of such shears does not require close tolerances .in order to obtain outstanding performance in operation.

this invention it is essential the blades be mounted for that the blades be capable of autogenous relative longitudinal movement, as the jaws are opened and closed, to permit of the cutting teeth as described. If theblades were locked against such relative longitudinal movement, the self-centering fea- For example, if both blades were anchored to one another by a guide rod, as in the Nikonow et al. patent or by a pin close-fitting with both blades as In accordance with in the Weidauer patent, both hereinbefore reon name g mbveinent Inasmuch as-soine teeth of bo'thjaws i are at all-time mesh, the consecutive-teeth im ta ed! be, "the reiationtf tire teeth-tithe two blades would be fixed and predetermined during e aration or the jaws and said teeth Wtiiild be ineaizghbl e :"of a serf -c ntering *dperation acc'ordihg p'res it invention While this i venues was primari-ly 'conceived $61 inc ribb'i aiti dn into shears of the compound 765C 1011 type shown Figures 1 6-, "said nvention lms iitil-ity in means of the, single action type, such as sht'av fn for e k-ample in Figures 7 "8 these la tt lgu'res, the shears embody blades '2' inept-asst levers having-relatively rigid handles Q! and 28 a -"d pivoted to the another by a raicrum pivot 29-. This pivotis i as trated as a bolt, although any other suitable-fillcrum pivot construction may be used.

The fulcrum bolt 29, preferably a shouldered bolt, is shown best in Figure 8 as passing snugly throu'gha circular hole as in the blade 2 6 and extending through e-lon ated slot 3 I in the other blade 25. The blades are th fts -e"onnected tor pivotal movement while permitting relative longitud inal movement. The teeth "of the serrated edgesof the cutting-fianges 32 and 33 are adapted torerhain atall times -i-r-1--mesh as hereinb'efore describedga stop -34 on the blade 26 serving ;to opening movement of the jaws and stop '35 2-8 'ser-v-i-ng to limit their closing will self-center one another as the jaws are opened and closed, and the elongated slot 3| will permit the longitudinal shifting of the jaws relative to one another to allow of this self-centering of the cutting teeth in the same manner as hereinbefore explained.

I have hereinbefore referred to the interposition of the spring washer 5 between the operating levers and arranged coaxially of the fulcrum pivot 3. This spring washer is not essential to the operation of shears according to this invention, but I preferably incorporate it because I have found that its presence permits even greater tolerances in the manufacture and machining of the shear parts.

It Will be apparent from the foregoing detailed description that, by mounting the two cutting blades of the shears for relative longitudinal movement and utilizing cooperating cutting teeth of the two blades to automatically relatively adjust the blades to effect self-centering of these teeth, I am able to accomplish cutting accuracy which could not possibly be obtained by either optimum manual adjustment of or fixed relation between the blades and this result is possible with ordinary production methods where tolerances are not always too close. I wish it understood, however, that the present invention may be incorporated to advantage even in high price shears made to close tolerances and lapped, for the incorporation of the invention in any shears wherein the cutting teeth do not leave mesh with one another will materially add to the cutting efiiciency of the shears.

The foregoing detailed description sets forth the invention in its preferred practical form, but the invention is to be understood as fully commensurate with the appended claims.

Having thus fully described the invention, what I claim as new and desire to secure by Letters Patent is:

'1. Compound action pinking shears comprising: cross levers fulcrumed where they cross and provided with handles, a captive blade pivotally connectedito trieiieter on the siee ortne and "both pivotally and iongttudmail autism connected to the other lever on the oppmite side of the fulcrum, and a follower place both pigmally and longitudinally slmabiy connected to path =1eve'rs on opposite sides of said fulcrum, whereby saidjfon'ower 1 at is capable or fi ee 'iongituaural move en ela we to tn captive biadegsafd blades 'h SfV-IHg cutting 'teeth at times in mesh aha-adapted to successively traverse one arrest-fer when the levers are piv'otally moved.

'2. Pih' king shears havi g 'ttcthed-eutt'ingbraee's with their teeth at all tini'es mesh, and ror'ednnecting "aid blades for 'pivotalfinoven ient and for unrestmcteu relativ'e ld ng'itudi-nal movement induced by the cgenous-se1r=ce te as; or the teeth (if-the re pective bla es a su-en pro ressively "mesh with one another uu'ring pivst l-movement bit-the blades. H v i rin king-snearsnavmg toothedcuttinfgblades with their teeth at al times in-mesh, "and connectin said blades tor both pivotal and um restrained longitudinal movement r mtive tofoir'e another, whereby the teeth of said blades autogenously move one biaue longitudinally with respent to othe other to the extent neee sary topersa idteeth to center themselves -as the temper one blade pr'o'gress-iveiymesh with the teethiff the other blade :duringpivotal movement tor 17116 blades.

4. Pinking shears comprising: a. captive blade and a follower blade pivotally connected and having teeth meshing at all times, and handles for causing said teeth to progressively engage one another when the blades are pivotally moved relative to one another, the captive blade being anchored against longitudinal movement relative to one handle and the follower blade being mounted for unrestricted longitudinal movement relative to the captive blade, whereby the teeth of the follower blade autogenously move that blade longitudinally as they progressively mesh with the teeth of the captive blade during pivotal movement between said blades.

5. Pinking shears according to claim 4, wherein the follower blade is also longitudinally movable relative to both handles.

6. Compound action pinking shears comprising: cross levers fulcrumed where they cross and provided with handles, a pair of meshing toothed cutting blades, one blade having pivot and slot connections with both levers on opposite sides of said fulcrum and theother blade having a pivot connection with one lever on one side of the fulcrum and a pivot and slot connection with the other lever on the other side of the fulcrum to mount said blades for both pivotal and free relative longitudinal movement with respect to one another to permit the teeth of each blade to automatically center themselves with respect to the teeth of the other blade as they progressively mesh during pivotal movement of said levers.

7. Pinking shears comprising: blades having cutting edges adapted to traverse one another as said jaws are opened and closed, said blades being mounted for free longitudinal movement with respect to one another to permit autogenous self-centering of the corresponding cutting teeth of the jaws as said teeth successively mesh with one another during closing and opening movement of the jaws, crossed levers fulcrumed to one another where they cross and connected to the blades for operating the same.

8. Compound action pinking shears comprislevers on ;opposite sides of said fulcrum by pin and slot connections permitting said follower blade free longitudinal movement relative to the captiveblade, said blades having cutting teeth which are at all times in mesh and are adapted to successively traverse one another when the levers are pivotally moved.

9. Pinking shears which comprise a pair of blades inclined to each other each having a row of teeth, said rows meshing with each other in shearing relation, handle members, and linkage ,means connecting said handle members to said blades said linkage means including apair of pivotally connected arms each ofwhich is movably connected to both blades, the points of connection being equidistant radially from the pivot point of said arms so as to move the blades laterally while holding the blades at approximately the same angle to each other, one of the connections of one arm to a blade being pivotal to prevent relative longitudinal movement of that blade while the correspondingly positioned connection of the other arm to its blade permits sufiicient longitudinal movement of the other blade mitting longitudinal to maintain said teeth in proper mesh with each other.

10. Pinking shears which comprise a pair of handle members connected together by a pivot with stubs extending beyond said pivot, a pair of blades carrying rows of cutting teeth that intersect with each other in meshing relationship, said blades being pivotally connected to said members and stubs to move the blades laterally as the handles are worked, one of said pivotal connections preventing longitudinal movement of one a of said blades and the corresponding pivotal connection between the other stub and blade permovement of the other blade.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Re. 23,503 Carney May 27, 1952 467,808 Heinrichs Jan. 26, 1892 846,854 Jones Mar. 12, 1907 1,107,227 Ryan Aug. 11, 1914 1,179,830 Nayes Apr. 18, 1916 1,918,889 Bacon July 18, 1933 1,970,408 Weidauer Aug. 14, 1934 2,048,170 Sibley July 21, 1936 2,290,203 Nickonow July 21, 1942 2,387,053 Brown Oct. 16, 1945 2,590,024

Lieberman Mar. 18, 1952 

